Circuit breaker



Feb. 19, 11935. w, DYER 1,991,884

0 IRCUIT BREAKER Filed Nov. 26, 1930 INVENTOR L/oyd W Dyer A ORNEYPatented Feb. 1 9, 1935 PATENT. OFFICE CIRCUIT BREAKER Lloyd W. Dyer,'Swlss'vale, 2a., assignor to Westinghouse Electrlc and ManufacturingCompany, a corporation of Pennsylvania Application November 26, 1930,Serial No. 498,386

9 Claims.

The invention relates to circuit interrupters and particularly tocircuit interrupters wherein the contacts are separated and the are isextinguished in an exceedingly short interval of time.

Application Serial No. 678,248 of H. L. Rawlins gled June 29, 1933 is adivision of this applica- One object of the invention is to provide acirc'uit interrupter, that operates at high speed, with anarc-extinguishing device that prevents arc reinitiation after the arc isextinguished, as the current passes through the zero point of its cyclewave.

Another object of the invention is to provide an arc-extinguishingdevice, for a circuit interrupter of the above-mentioned type, that willtrap the arc-extinguishing fluid about the arc in such manner that thefluid will be decomposed by the are for effecting the liberation ofun-ionized gas which passes through the arc stream.

A further object of the invention is to provide anarc-extinguishing-device, for a circuit interrupter of theabove-mentioned type, that shall maintain the arc in its originallyestablished path and cause the gas resulting from decomposition of thesurrounding liquid to pass through the arc stream.

The trend of the art, relative to electric-transmission systems, istoward circuits of higher voltages. One of the greatest limitations tothe continued increase of the voltage ratings of such systems is, nodoubt, the inadequacy of the circuit-interrupting equipment, the presentcircuit interrupters b ing incapable of reliably handling the moredesirable high voltages,

The tremendous power that is developed in the modern high-voltagesystems, in the presence of a short circuit condition, must bedissipatedand the arc extinguished in an exceedingly short interval oftime and prevented from re-striking if no harmful results are to ensue.Violent surges usually occur when several cycles of alternating currentoccur before the arc is completely interrupted. If the present type ofcircuit interrupter.

is made large, in proportion to the increased voltage of the system, theclearances between the live conductors and the grounded enclosingcasings .will be increased to such an extent that the entire structurewill assume undesirable proportions.

In practicing the invention, I avoid the necessity of increasing thesize of the higher-voltage circuit-interrupting structures by decreasingthe time requiredto interruptthe circuit. I accomplish this byincreasing the speed of contact travel to procure a. more rapidseparation of the contact members and employ are de-ionizing devices forextinguishing the arc upon the occurrence of the first zero .point inthe current a1ter--' nating cycle wave and which prevent the are frombeing reinitiated after extinguishment. In such construction, thecircuit is interrupted almost immediately upon the occurrence of apredete mined circuit condition, before excessive press es-are permittedto accumulate, and no deleterious effects from surges result in thesystem or in the circuit-interrupting structure.

The invention will be best understood by referring to the followingspecification, taken in conjunction with the accompanying drawing,wherein:

Figure 1 is an elevational view, partially in section, of a circuitinterrupter embodying features of the invention.

Fig. 2 is a sectional view, in elevation, of the arc-extinguishingstructure.

Fig. 3 is a sectional view of the structure illustrated in Fig. 6, takenalong the line III-III thereof.

The invention comprises, in general, a tank 1 having a cover 2 thatsupports insulated conductor bushings 3. Arc-extinguishing devices 4 areprovided on the ends of the bushings 3, having contacts 5 thereofbridged by conducting contact rods 6 and a bridging member 7 to completethe circuit. The bridging member 7 is supported on a lift rod 8 that isreleasably retained against the bias of anaccelerating mechanism 9 by alatching mechanism 11, all of which elements are contained within thetank 1. The tank is also provided with an arc-extinguishing liquid 12 inwhich the arc-extinguishing devices 4 are immersed.

In Patent No. 1,872,382 issued August 16, 1932 on an application ofCh'ristain Aalborg et al. and 40 assigned to the assignees of thepresent invention, a high-speed circuit interrupter is set forth, aportion of the mechanism of which is disclosed in Fig. 1. In thisstructure, the movable members are made as light as possible, in view ofthe strength and conductivity requirements.

'hardened copper is employed for the contact rod 6 and bridging member7, while wood micarta is employed in the lift rod 8. The reduction ofweight in the moving parts decreases their inertia and permits theirrapid acceleration by the accelerating mechanism 9.

A metal rod 13 is attached to the upper end of the collar 14 whichsupports the lift rod 8. The accelerating mechanism 9 surrounds the rod13 and comprises an outer spring and an inner spring 16 between which asleeve 17 is utilized to prevent the turns of one spring frominterfering with those of the other. The springs 15 and 16 are disposedbetween a flat washer or bumper plate 18 in the housing 19 and a washer23, which abuts the collar 14 on the lift rod 8 and serves to force themovable contacts downwardly, at high velocity, when the rod 13 isreleased. The housing 19 is secured to the side of the tank 1 by bolts22. and a suitable retaining and guiding structure 24 is provided aboutthe springs 15 and 16.

The upper end of the rod 13 is provided with a metal head 25 which maypass through an opening 26 in the housing 19, and the rod 13 isreleasably retained in closed position by a latch 27, a portion of whichis cut away to form a recess 28, in which a steel ball 29 is forced bythe action of a cam 31 that is biased upwardly by the spring 32 as ismore fully described in the above-noted copending application, thisconstruction makes the movable contacts and bridging bar trip free ofthe closing mechanism at the top of the lift rod so that the mechanismconnecting the lift rod to the closing mechanism-does not have to beaccelerated when the breaker is tripped.

The operation of the device will now be described. When the tripping arm39 is actuated, the cam 31 is forced downwardly against the spring 32,thereby releasing thesteel ball 29 and the latching member 27 tocompletely release the accelerating mechanism 9 and the lift rod 8. Thetension in the springs 15 and 16, acting between the washers 18 and 23,causes the bridging bar 7 and conducting rods 6 to be rapidlyaccelerated downwardly to establish arcs between the ends of the rods 6and the stationary contact member 5. When the plate 23 has reached itslowermost position, the head 25 strikes against the bumper plate 18, andthe continued movement of the accelerated members causes the springs 15and 16 to be compressed and the movement of the members retarded andbrought to rest without damage to the members.

The arc-quenching medium 12, that may be oil, water or any othergas-evolving substance, is retained in intimate contact with the are bythe plates 56 which divide the chamber 4 into a series of sub-chambers63 which communicate with each other only through the openings 62 whenthe contact rod 6 is withdrawn. In this construction, the arc is beingdrawn into fresh sections of the liquid, and the gas evolved from theliquid, owing to its intimate contact with the arc, passes through thearc stream and escapes through the openings 64.

The un-ionized gas, passing longitudinally throughv the arc stream,de-ionizes the stream and causes the are core to contract.

This de-ionizing process and the contraction of the core continues untila zero point of the cycle wave occurs, at which time, the arc isextinguished. As the cross-section of the are core is exceedingly smallat this moment, complete deionization of the arc path immediatelyoccurs, and reinitiation of the arc isprevented when the current andvoltage again increase in value. In this construction, an arc isestablished and completely extinguished within one cycle of alternatingcurrent. I

When the contact members are moved within thearc-deionizing-and-extinguishing device at an exceedingly high rate ofspeed, similar to that effected by the disclosed accelerating mechanism,

.will be completely consumed at the portion of the are stream where thearc is initially established,

and, for this reason, a greater length of arc will be required. Whenemploying the high-speed contact movement in combination with the gridstructure, the structure and the contact travel may be shortened,because of the fact that the critical arc length only will be requiredto effect complete arc extinguishment.

The constructional details of the arc-extinguishing device, thatutilizes the accumulated gases for accelerating the deionizationprocess, are illustrated in Figs. 2 and 3, wherein a receptacle 55encloses a plurality of spaced plates or units of plates. In Fig. 2,separate plates 56 are joined to the walls of the receptacle 55 and arespaced apart by insulating bushings 5'? that cover through bolts 58.

An upper chamber 59, between the receptacle cover 61 and the topmostplate 56 is unvented except for an opening 62 through which the arc isdrawn. A plurality of chambers 63, provided below the chamber 59, arevented by small orifices 64 contained in the periphery of thereceptacles 55, as shown in Figs. 2 and 3. When the arc is drawn throughthe alined holes 62 in the center of the plates 56, as the rod 6 ismoved downwardly from engagement with a stationary contact member 65,gases are generated by the decomposition of the liquid trapped in thechambers 59 and 63.

As the arc is drawn in the successive chambers, the gas, evolved uponthe decomposition of the trapped liquid, builds up a pressure andescapes to the adjacent lower chamber, wherein high pressure has at thattime not yet been developed. For this reason, the gas must pass throughthe arc stream at each of the central openings 62 in the plates 56 asthe contact rod 6 clears each opening 62. In this construction, thegases under pressure pass longitudinally through the arc stream at'thesame time that gas is being fed radially thereinto as the liquid in theparticular chamber is being decomposed. The vents 64 from the individualsub-chambers come into use successively as the contact rod 6 clears eachopening 62 and vent the gases laterally and radially from each of thesub-chambers as pressure is built up after the arc has been drawnthereinto.

The i'ntermingling of these gases produces a turbulent motion within thearc path that more rapidly effects the recombination of the ions in thearc path, than is effected when the radially supplied gas alone ispassing therethrough. After the gases become heated and ionized, theyare forced out of the arc stream by the fresh gases that are continuallybeing evolved and are vented from within the receptacle 55 through vents64 that are provided along the side walls thereof.

It will thus be seen that I have provided a circuit interrupter that iscapable of interrupting circuits of exceedingly high-voltage ratings. Iaccomplish this interruption by means of an accelerating mechanism thateffects rapid sep aration of the contact members and substantially orgas thereirom at a plurality of points around instantaneous arcestablishment, and by the deionizing means which extinguishes the arc inthe first hall cycle of alternating current occurring after contactseparation. I eifect this extinguishment by supplying un-ionized gas tothe arc stream, longitudinally and radially thereof, that turbulentlypasses through the arc stream and causes the hot ionized gases thereofto become cool and de-ionized;

While I have described one particular embodiment of the invention, it isto be understood that many changes, additions, omissions andsubstitutions may be made therein without departing from the spirit andscope of my invention, as set forth in the accompanying claims.

I claim as my invention: r 1. The combination with separable contactmembers 'of a circuit interruptengof a plurality of spaced insulatingmembers having openings.

through which the contact members extend, an insulating chamber havingventing means on all sides thereof for enclosing the said members, and agas evolving substance within said chamber.

2. The combination with separable contact members of a circuitinterrupter that extend through slots in a plurality of spacedinsulating members, of an insulating chamber having vents in its sidesfor-supporting and closely engaging the said insulating memberssaid'vents being positioned around the periphery and along the length ofsaid chamber.

3. An insulating chamber associated with the arc-quenching liquid of acircuit interrupter, a plurality of sub-chambers formed within thechamber by a plurality of insulating Plates having central openings,therein and the main portion of the outer periphery of each of saidsubchambers being closed, a movable contact member extending throughsaid openings, and vents in the sides of the chamber communicating withthe said sub-chamber for permitting radial flow the periphery of thechamber after the arcis 4. An insulating chamber submerged in thearc-quenching liquid of a circuit interrupter and a major portion of theouter periphery of saidchamber being closed, a plurality of sectionswithv the, liquid, longitudinally through the are,

stream, and means for venting the gas radially through the side walls ofsaid chamber through-. out its length and at a plurality of pointsaround its perip ry.

- 5; In a circuit interrupter, an arc-extinguish-'ingchamberhavlngthemaior portionofitsside walls normallyclosed and aplurality of sub-' chambers formed therein by a plurality of insulatingplates having openings therethrough, means ior drawing an are throughsaid openings, said are drawing means having about the samecross-sectional area as said openings, and means forindividually-venting each of said sub-chambers through the side wall ofsaid chamber site 7 the are is drawn. v

8. In a circuit interrupter, an arc extinguishing chamber having themajor portion of its side walls normally closed and a plurality ofsubchambers formed therein by a plurality of insulating plates havingopenings therethrough, means for drawing an are through said openingsinto each of said sub-chambers successively, the area of said openingsbeing not greatly in excess of the cross-sectional area of said meansfor drawingthe arc,'and means for venting each of said sub-chamberslaterally through the side wall of the chamber.

7. In a circuit interrupter, an arc extinguishing chamber having a sidewall of insulating material and a plurality of partitions of insulating'material dividing said chamber into a plurality .of sub-chambers, saidpartitions having aligned openings therethrough, a contact memberfixedly mounted adjacent one endof said chamber andacontactmembermovablethroughsaidalignedopeningstodrawanarcfromsaidfixedlymoimtedcontactintosaidsub-chambersin"meanspermittingflowoffiuidradialiythrough said side walls of said at anumber of 3 points therearotmd and which function successively as thearc is drawn into said sub-chambers.

8. In a circuit interrupter, an arc extinguishing chamber having themajor portion of its side walls normally closed and a plurality ofsubchambers formed therein by a plurality of insulating plates havingopenings therethrough, means for drawing an are through said openings,

and means for individually venting each of a' plurality of saidsub-chambers through the side wall of said chamber after the arc isdrawn, some of said venting means being through one sideoi 'the chamberand other of said venting means being through theopposite side of saidchamber.

9. In a circuit interrupter, an arc extinguishing chamber having themajor portion of its side walls normally closed and a pluralityotsubchambers formed therein by a plurality of insulating plates havingopenings therethrough, means for drawing an are through said openingsinto each of said sub-chambers successively, and means for ventingeach-of a plurality of said. sub-chambers laterally through the' sidewall of the chamber, and adjacent sub-chambers having at least a partofv said venting means through op-- posite side walls of the chamber.

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